我正在尝试在 gridView 中显示一些图像，这些图像来自对 ElasticSearch 服务器的研究。所以我在我的第一个活动中有一个文本字段 + 按钮，当我单击该按钮时，一些与文本字段中的关键字相关的图像会打印在网格视图中。
到目前为止，我可以进行研究，并且在 gridView 中显示了一些图像，但是在向下/向上滚动或进行其他研究后，我的应用程序崩溃（内存不足）。我想我必须分别解决这两个问题。对于第一个（向上/向下滚动），我想记住缓存中的位图（http://developer.android.com/training/displaying-bitmaps/cache-bitmap.html）。对于第二个问题，我不知道该怎么办。欢迎所有建议/想法。
当我在缓存中记住图像时，我仍然遇到问题，当我向下滚动和向上滚动后，不再显示图像，并且 catlog 中没有错误。
AndroidGridLayoutActivity.java
public class AndroidGridLayoutActivity extends Activity {
ImageAdapter imgAdapter =new ImageAdapter(this);
GridView gridView;
private static LruCache<String, Bitmap> mMemoryCache;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.grid_layout);
gridView = (GridView) findViewById(R.id.grid_view);
// Get memory class of this device, exceeding this amount will throw an
// OutOfMemory exception.
final int memClass = ((ActivityManager) getApplicationContext().getSystemService(Context.ACTIVITY_SERVICE)).getMemoryClass();
// Use 1/8th of the available memory for this memory cache.
final int cacheSize = 1024 * 1024 * memClass / 8;
mMemoryCache = new LruCache<String, Bitmap>(cacheSize) {
@Override
protected int sizeOf(String key, Bitmap bitmap) {
// The cache size will be measured in bytes rather than number of items.
return bitmap.getByteCount();
}
};
}
public void sendMessage(View view){
imgAdapter.clearmThumbIds();
gridView = (GridView) findViewById(R.id.grid_view);
EditText editText = (EditText) findViewById(R.id.searchBar);
String message = editText.getText().toString();
try {
eSearchElastic.ESE(imgAdapter,message,gridView,0);
} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println("SendMessage is ok poiuur ca");
}
public static void addBitmapToMemoryCache(String key, Bitmap bitmap) {
if (getBitmapFromMemCache(key) == null) {
mMemoryCache.put(key, bitmap);
}
}
public static Bitmap getBitmapFromMemCache(String key) {
return mMemoryCache.get(key);
}
}
ImageAdapter.java
public class ImageAdapter extends BaseAdapter {
static private List<String> urlList = new ArrayList<String>();
private Context mContext;
Bitmap bmImg;
static private List<String> mThumbIds = new ArrayList<String>();
public void addmThumbIds(String url) {
mThumbIds.add(url);
}
public void clearmThumbIds() {
mThumbIds.clear();
}
public String getmThumbIds(int position) {
return mThumbIds.get(position);
}
// Constructor
public ImageAdapter(Context c) {
mContext = c;
}
@Override
public int getCount() {
return mThumbIds.size();
}
@Override
public Object getItem(int position) {
return mThumbIds.get(position);
}
@Override
public long getItemId(int position) {
return 0;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
ImageView imageView;
if (convertView == null) {
imageView = new ImageView(mContext);
} else {
imageView = (ImageView) convertView;
}
System.out.println("Poisition " + position);
downloadFile(imageView, mThumbIds.get(position));
imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
imageView.setLayoutParams(new GridView.LayoutParams(135, 135));
imageView.setPadding(0, 0, 1, 0);
return imageView;
}
void downloadFile(final ImageView imageView, final String fileUrl) {
AsyncTask<Object, Object, String> task = new AsyncTask<Object, Object, String>() {
@Override
protected String doInBackground(Object... params) {
System.out.println("TEST 1 : begining background");
if (!urlList.contains(fileUrl)) {
urlList.add(fileUrl);
URL myFileUrl = null;
try {
myFileUrl = new URL((String) params[0]);
} catch (MalformedURLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
HttpURLConnection conn = (HttpURLConnection) myFileUrl
.openConnection();
conn.setDoInput(true);
conn.connect();
InputStream is = conn.getInputStream();
bmImg = BitmapFactory.decodeStream(is);
} catch (IOException e) {
e.printStackTrace();
}
} else {
System.out.println("TEST 2");
bmImg = AndroidGridLayoutActivity
.getBitmapFromMemCache(fileUrl);
}
return null;
}
protected void onPostExecute(String unused) {
System.out.println("TEST 2 : begining postexecute");
imageView.setImageBitmap(bmImg);
if (!urlList.contains(fileUrl)) {
AndroidGridLayoutActivity.addBitmapToMemoryCache(fileUrl,
bmImg);
}
}
};
task.execute(fileUrl);
}
}
网格布局.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<EditText
android:id="@+id/searchBar"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:hint="@string/Search_hint"
android:inputType="text"
android:imeOptions="actionSend" />
<Button xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/button_send"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/button_send"
android:onClick="sendMessage" />
<GridView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/grid_view"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:numColumns="auto_fit"
android:columnWidth="90dp"
android:horizontalSpacing="10dp"
android:verticalSpacing="10dp"
android:gravity="center"
android:stretchMode="columnWidth" >
</GridView>
</LinearLayout>
如有需要 eSearchElastic.java
public class eSearchElastic {
static private List<String> idRowKey = new ArrayList<String>();
public static void ESE(final ImageAdapter imgAdapter, final String keyword,
final GridView gridView,final int from) throws ClientProtocolException,
IOException {
AsyncTask<Void, Void, Void> task = new AsyncTask<Void, Void, Void>() {
private String rowKey;
private int i =0;
private int imageAlreadyPrinted =0;
private int size=10;
@Override
protected Void doInBackground(Void... params) {
String server = "server";
String index = "images";
String type = "images_schema_1";
System.out.println("\n\n KEYWORD " + keyword + "\n\n");
String query = "{\"sort\" : [ {\"confidence_level\" : {\"order\" : \"desc\"} }],\"from\" : "+from+", \"size\" : "+size+",\"query\" : {\"text_phrase\" : { \"keyword\" : \""
+ keyword
+ "\"}},\"filter\" : {\"numeric_range\" : {\"confidence_level\" : { \"from\" : 10, \"to\" : 100, \"include_lower\" : true, \"include_upper\" : true}}}}'";
ElasticConnection connection = new ElasticConnection(server, index, type);
ElasticQuery elasticQuery = new ElasticQuery(query);
ElasticResponse response = null;
try {
response = elasticQuery.getAnswer(connection);
} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
String[] fields = { "url"};
List<ElasticResult> results = null;
try {
results = response.getAnswer(fields);
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
for (ElasticResult res : results) {
System.out.println("ICI "+from+ " " + res.getField("url"));
rowKey = res.getId();
System.out.println(res.getId());
if (rowKey != null) {
if (idRowKey.contains(rowKey)) {
if(imageAlreadyPrinted<size && i==size-1)
try {
ESE(imgAdapter,keyword,gridView,from+10);
} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println(rowKey);
continue;
} else {
imageAlreadyPrinted++;
addidRowKey(rowKey);
imgAdapter.addmThumbIds(res.getField("url"));
}
}
i++;
}
System.out.println("-----FIN esearch");
return null;
}
@Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
gridView.setAdapter(imgAdapter);
}
};
task.execute();
}
public static void addidRowKey(String url) {
idRowKey.add(url);
}
public void cleaidRowKey() {
idRowKey.clear();
}
public String getidRowKey(int position) {
return idRowKey.get(position);
}
}